Car and truck manufacturers have offered the option of electrically operated door locks for a number of years. This option has enjoyed widespread popularity for two reasons: 1, with the push of one button the operator can lock and unlock all door locks simultaneously and 2, the system lends itself to remote operation so that the operator can lock and unlock all doors from outside of the vehicle with a radio signal. This feature however has never been offered for the lock of the tailgate of pick-up trucks. As a result of the paucity of factory installed power tailgate locks, there have been a number of aftermarket manufacturers who have tried to adapt electrically operated mechanisms to lock and unlock the tailgate.
Tailgate construction consists typically of a box structure that extends the width of the truck and is hinged horizontally along the bottom edge to provide access to the cargo area when folded down. A horizontal stiffening strut ties the front and rear faces of the tailgate to prevent flexing of the two faces. The tailgate is secured in the closed position by two catches on the sides of the tailgate. The catches are released by two control rods leading to a centrally mounted latch assembly. The control rods and the latch assembly are mounted in the horizontal cavity that extends the whole length of the tailgate defined by the stiffening strut and the sides
This cavity presents little limitation to the width of any power lock that is intended to be mounted alongside an existing latch assembly. As a result, prior art power locks, as shown in U.S. Pat. No. 5,174,619 and U.S. Pat. No. 5,295,374 have been constructed with the linear actuator and the associated control linkages positioned horizontally.
However new truck designs, as described in U.S. Pat. No. 6,918,624 may include a fold-out step stored inside the tailgate which severely limits the space available for a lock installation. The fold out step retracts into two vertical channels positioned in close proximity to the latch assembly and interfere with the installation of a power lock as described in the prior art. This restriction in a lateral direction is compounded by the restriction imposed vertically by the already existing stiffening strut.
A need exist, therefore, for a very compact power lock that can be installed in a tailgate with the space limitation resulting from the presence of a fold out step.